Currently operational communication networks use the large information carrying capacity of optical fibers to transport the world's data traffic. However, routing and switching are still performed by electronic circuits. In the future it is anticipated that communication networks, such as those related to radar and image transfer, will exploit hugh bandwidths that would be unmanageable through the use of electronic circuits.
Known devices for manipulating optical signals include optical delay lines. However, these optical delay lines utilize field side coupling of open dielectric resonators to create the delay line. Furthermore, installation of these devices is relatively complicated because the resonators need to be carefully placed on a plane surface to insure good coupling between them. The distance between the resonators is required to be controlled with nanometer accuracy because the evanescent field has approximately a hundred nanometer range. In addition, the temperature of the resonators is required to be kept stable and equal between neighboring resonators because temperature fluctuations and gradients result in a mode motion that leads to destruction of the properties of the waveguide. For these reasons, known optical delay lines have only been capable of achieving very short delay times on the order of tenths of a second. They are also characterized by relatively large absorption.
Delay lines characterized by resonant structures formed by photonic band gap materials have also been proposed. However, when implemented, these systems have also been characterized by very short delay times and relatively large absorption.
Accordingly, a need exists for an optical device that can operate as an efficient optical delay line. More generally, a need exists for an optical device that can delay, store, and buffer optical pulses and, thereof, can operate to route and switch optical data signals.